Create floorplan from existing building

I have created a 3D floor plan of my building however when I create the walls using the offset tool I loose floor space. Original dimensions were created with the rectangle tool then I used offset tool to make the walls.

Do I need to account/add half the thickness of each wall in each room so when I use the offset tool the finished product is the correct size?

Edit: I measured inside room from face to face of the finished walls in each room, Walls are 4 3/4" thick. (2x4 and 5/8 sheetrock)


Hard to say. It all depends on how you went about measuring. If you measured a room, for example, from finish face of wall to opposite finish face of wall, you should model that and not subtract from it. You need to measure thickness of the wall and model that, and then the next room, etc. I always shoot for the biggest over all dimension I can get, and subdivide back from that.

You can’t have measured dimensions from “half the wall”, the inside where mice live. So you either used inside dimensions or outside dimensions to create your floor plan (or a mixture). What to do with the offset value and direction can’t be answered without more information about what you did.

updated original post. Thanks

Measured each room and Hallway from finished inside wall to finished inside wall. Wall thickness is 4 3/4" thick

Offset the edges to the outside instead of the inside and you’ll be fine.

Thanks, for the exterior walls this fine, however for the interior walls side by side offices it does not work as well.

Again it depends in part how you measured, how accurate your methods, and how whacky the building may or may not be.

1 I use a Leica Disto for speed and accuracy, and a steel tape for little stuff.
2 It’s important to get the over all dimensions accurately first. I measure the exterior with a piece of foamcore stuck to the corners as a target for the Disto, and on the interior look for the longest line-of-sight stretches I can get with the laser.
3. If you measure 10~20 smaller things and add them up, whatever error is built into your measurements could be amplified 10~20 times in the over all total, so I never use that as a way to get the bigger over all dimensions. Instead I work backwards from the over all dimensions with the smaller stuff, and sometimes have to fudge those numbers a little bit here and there for it to all fit. If everything is done accurately enough, you shouldn’t have to fudge things a lot. If a building is significantly out of square and what not, it gets a lot more challenging.

Bottom line: Yes, some fudging, but how much are you ending up off by?

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For floorplans I only use the offset tool for the outer walls. Then for the inner walls, I use guidelines.

Another method for recording existing building layout relationships is to use “running dimensions”. This tends to ensure accuracy, obviates the need to provide finite dimensions between measurement locations, and may save time in some cases.

Simply put, this method records the reading of the tape at each “station point” without concern for the distance between walls, corners, doors, windows, etc. I would normally provide an illustrative example, but none is handy at the moment, so I will try to verbally explain.

Let’s say you want to measure a classroom wing across an intervening hall:
Start at inside FOW (face of wall)
hit next FOW (18’-6")
next FOW (19’-0") … wall is 6" thick
cross corridor FOW (25’-0") … hall is 6’-0"
next FOW (25’-6’") … wall is 6" thick
hit next inside next FOW (44’-0") … classroom is 18’-6"

When I develop EC plans using this method, the tape readings (the dimensions shown above in parentheses) are indicated (and not the actual dimensions until the final stage of CAD document preparation).

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